Hybrid Breast Augmentation: A Reliable Formula for Preoperative Assessment of Fat Graft Volume Based on Implant Volume and Projection.

[BACKGROUND] Autogenous fat grafting (AFG) is an established technique used as an adjunct to breast augmentation (BA) to redesign breast shape. Surgeons often use experience and intuition to estimate AFG volume, which can result in incorrect assessment of donor areas and unnecessary fat removal.

[OBJECTIVES] This aim of this study was to develop a method based on a mathematical formula, which utilizes implant volume and projection to predict AFG volume.

[METHODS] Thirty patients (60 breasts) underwent primary hybrid BA. A software package (SketchUp) was used to simulate 3-dimensional AFG and implant volumes, which in turn were used to develop an equation for estimating AFG volume according to 3 different implant projections. The results for each group were compared, via Pearson's correlation coefficient, with the results of the clinical series.

[RESULTS] All patients received Motiva Ergonomix SmoothSilk/SilkSurface implants, ranging in volume from 175 to 355 cc (mean, 265 cc), as well as an average AFG volume of 79.2 cc/breast (range, 50-110 cc). Twenty-nine patients (96.6%) were either very satisfied or satisfied during a mean follow-up of 18 months (range, 6-28 months). A high correlation was observed between the AFG performed in the cohort and predictions obtained from the formula (r = 0.938, P < 0.001).

[CONCLUSIONS] The AFG volume in hybrid BA procedures can be estimated utilizing measurements based on implant volume/projection. This low-cost method can be applied to guide surgical decision-making in patients who are candidates for BA.